Flow condition

[clun]

A flowrate unit Nm3/h was quoted from a Air presurization unit manual.
I know that Normal cubic meter per hour., Nm3/h is Flow of free air measured at some reference point and converted to a standard set of reference conditions (e.g., 14.4 psia, 20° C, and 60% relative humidity.) Normal means m3/h at specified conditions. However,in the United states, the usual (normal/standard) is 14.696 psiA and 60/70°F. Some chemical engineers will use one atm and 0°C, but usually will be specific about the reference point. Europeans normally use one atm and 0°C. It is not the same to all people, so I know it is best that the reference pressure and temperature be definitely specified.
But does someone know that there are any guideline from FAA/JAA/CAA for this issue?

 

[aviat]

Aviation uses the ICAO standard atmosphere, last revised in 1976. Standard is for 40 degrees latitude at mean sea level, 0% relative humidity (dry air), 15 degrees C or 59 degrees F, 1013.25 mill bars or 29.291 inches of mercury pressure, and density of 1.225 Kg/m3 or 0.002378 slugs/ft3. There are charts and calculators available on the Internet to get other values.